Jimmy Fallon officially replacing Conan O'Brien!

The word is out among the NBC brass: As rumored and bounced around for some time, Jimmy Fallon is set to take Conan O’Brien’s job as host of "Late Night" in 2009. It’s a done deal.

Conan, of course, will be taking over for Jay Leno, who will leave the "Tonight" show in May 2009 as part of a forced retirement.

There’s much debate about letting Leno leave NBC etc., but right now let’s just concentrate on Jimmy. He’s the perfect successor to Conan and should have just as big an audience when he takes the reins. Fallon is one of those great underrated performers. This should be the right milieu for him.

I’m told NBC will make the formal announcement about Fallon around May 11 or 12, when the network presents the fall '08 schedule to advertisers here in New York.

Fallon, who recently married producer Nancy Juvonen, is said to be thrilled and ready, if not a little scared, about taking Conan’s desk. He still has to pick a producer and a band, among other things.

As for Leno, he has plenty of options. One of them might be to replace "Nightline" on ABC, pushing Jimmy Kimmel back to 12:30 a.m. But a lot can happen between now and May 2009 in the chess game they call TV programming.